Formats

AirSwap orders are mutually signed instructions to perform an atomic swap. Prior to execution, both the signer (party that creates and signs the order) and sender (party that sends the order to the EVM) must have approved the swap contract to transfer the specified tokens on their behalf.

Properties

An OrderERC20 has the following properties:

Property	Type	Description
nonce	uint256	Unique per signer and usually sequential.
expiry	uint256	Expiry in seconds since 1 January 1970.
signerWallet	address	Wallet that sets and signs terms.
signerToken	address	Token that the signer transfers.
signerAmount	uint256	Amount that the signer transfers.
senderToken	address	Token that the sender transfers.
senderAmount	uint256	Amount that the sender transfers.
v	uint8	v value of the ECDSA signature.
r	bytes32	r value of the ECDSA signature.
s	bytes32	s value of the ECDSA signature.

Execution

Orders are passed to the SwapERC20 contract for execution, which emits a SwapERC20 event on success. The swapLight function is more efficient, whereas the swap function provides protocol fee rebates to staked AST holders. Either function can execute a properly signed order.

  function swapLight(
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    address signerToken,
    uint256 signerAmount,
    address senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

Signatures

AirSwap signatures are EIP712, which includes a domain separator to avoid replays across chains.

TypeScript. Swap signatures in TypeScript can be created using the @airswap/utils package.

import { UnsignedOrder, createOrderERC20, createOrderERC20Signature } from '@airswap/utils'

const order = createOrderERC20({
  nonce: string,
  expiry: string,
  signerWallet: string,
  signerToken: string,
  signerAmount: string,
  protocolFee: string,
  senderWallet: string,
  senderToken: string,
  senderAmount: string,
})

const { v, r, s } = createOrderERC20Signature(
  order: UnsignedOrder,
  privateKey: string,
  swapContract: string,
  chainId: string,
)

Python. Swap signatures in Python can be created using the py_eth_sig_utils package.

from py_eth_sig_utils.signing import *

SIGNER_KEY = "0000000000000000000000000000000000000000000000000000000000000000"
SWAP_CONTRACT = "0x0000000000000000000000000000000000000000"

DOMAIN = "SWAP_ERC20"
VERSION = "4"
CHAIN_ID = 1

order = {
  "nonce": 0,
  "expiry": 0,
  "signerWallet": "0x0000000000000000000000000000000000000000",
  "signerToken": "0x0000000000000000000000000000000000000000",
  "signerAmount": 0,
  "protocolFee": 0,
  "senderWallet": "0x0000000000000000000000000000000000000000",
  "senderToken": "0x0000000000000000000000000000000000000000",
  "senderAmount": 0
}

data = {
  "types": {
    "EIP712Domain": [
      { "name": "name", "type": "string" },
      { "name": "version", "type": "string" },
      { "name": "chainId", "type": "uint256" },
      { "name": "verifyingContract", "type": "address" },
    ],
    "OrderERC20": [
      { "name": "nonce", "type": "uint256" },
      { "name": "expiry", "type": "uint256" },
      { "name": "signerWallet", "type": "address" },
      { "name": "signerToken", "type": "address" },
      { "name": "signerAmount", "type": "uint256" },
      { "name": "protocolFee", "type": "uint256" },
      { "name": "senderWallet", "type": "address" },
      { "name": "senderToken", "type": "address" },
      { "name": "senderAmount", "type": "uint256" },
    ]
  },
  "domain": {
    "name": DOMAIN,
    "version": VERSION,
    "chainId": CHAIN_ID,
    "verifyingContract": SWAP_CONTRACT,
  },
  "primaryType": "OrderERC20",
  "message": order,
}

v, r, s = sign_typed_data(data, bytes.fromhex(SIGNER_KEY))

Authorized Signers

Optional. One account may authorize another account to sign orders on its behalf. For example, a server might sign using an account that has been authorized by a contract wallet. To manage signer authorizations, use the following functions on the SwapERC20 contract.

function authorize(address signer) external
function revoke() external

EIP712

The following values are used for the EIP712Domain.

Param	Type	Value
name	bytes32	SWAP_ERC20
version	bytes32	4
chainId	uint256	Ethereum Mainnet: 1, Goerli: 5
verifyingContract	address	SwapERC20 address